MEDICAL MATTERS Muiris HoustonFurther to my recent column on the health benefits of exercise and my call for a facility to "prescribe" exercise in the same way drugs are prescribed, the Faculty of Sports and Exercise Medicine at the Royal College of Physicians in Ireland (RCPI) has been in touch to say it too is in favour of formal exercise prescribing by GPs.
Also in contact was Prof Chris Bell who, as well as being professor of physiology at Trinity College Dublin, is director of the cardiovascular health unit there. He and his fellow researchers presented an interesting study to the British Hypertension Society meeting last week. It examined the importance of maintaining exercise for people who have completed rehabilitation programmes following heart attack or cardiac surgery.
A group of healthy 18 to 21-year-old sedentary male college students took part in four weeks exercise training that involved cycling at a moderate rate for 30 minutes three to four times a week. Blood pressure and cardiac workload were measured during the training and for a number of weeks after training stopped.
Interestingly, the maximum benefits of exercise were seen within two weeks of starting training; both systolic and diastolic blood pressure dropped by an impressive 10mm Hg (mercury) from an average 120/66 to 110/57. However, when the training stopped, there was an equally rapid return to pre-training levels, with both cardiac workload and blood pressure rising again within weeks of stopping the exercise.
The good news in the research is that substantial cardiovascular benefits can be obtained rapidly by starting an exercise regime. But the bad news is how quickly the benefits are lost again when a person returns to a completely sedentary lifestyle.
"What shocked us a little bit was that the blood pressure lowering was not maintained. Cardiac rehabilitation programmes finish after eight weeks, leaving the difficult issue of how to ensure that patients continue to exercise at a sufficient level after a supervised programme terminates," Prof Bell says.
In an effort to establish the lowest level of exercise that will maintain cardiovascular benefits, he and his colleagues plan to expand their research to various age groups. They will look at healthy young people, healthy older people and those with borderline high blood pressure who are not taking medication for hypertension.
"If we can get evidence of the lowest level of exercise that will maintain benefits, then it is likely we can increase people's compliance with what might be 'easier' exercise regimes," Prof Bell says, adding that an added advantage of this approach would be a welcome increase in individual and community responsibility for health.
The Trinity group is now recruiting volunteers. If you would like to take part in the research, please e-mail physiol@tcd.ie or telephone (01) 6082723.
Moving away from exercise, but sticking with the cardiac theme, last week's Lancet had a significant piece of research outlining the specific benefits of taking statins, the group of drugs used to lower cholesterol.
In an analysis of 14 randomised trials involving over 90,000 patients, researchers from Oxford and Sydney concluded that the greater the reduction of LDL (bad) cholesterol achieved by statin therapy, the greater the reduction in major cardiovascular events, such as heart attack and stroke.
The study confirms that anyone with heart disease, regardless of their cholesterol level, could benefit from statins. And it even links the benefits directly with the actual reduction in cholesterol: statin treatment could reduce the five-year incidence of heart attack, stroke or the need for bypass by almost one-fifth for every one millimole/litre (mmol/l) reduction in LDL cholesterol.
In absolute terms, this translates into 48 fewer people developing a cardiac problem for every 1,000 patients with pre-existing heart disease treated with a statin.
Until now doctors used statins to bring levels of "bad" cholesterol to below 3mmol/l. This research is likely to prompt a more aggressive use of the drugs in people with pre-existing heart disease in an effort to lower the risk of a recurrence.
Finally, and on a lighter and more artistic note, comes news of a pleasurable way to protect against heart disease. Researchers from Italy and the UK, writing in the current edition of the medical journal Heart, describe the effects of different kinds of music on the cardiovascular system. They assessed various aspects of breathing and circulation in 24 young men and women, both while and after they listened to short excerpts of music. Participants listened to raja (Indian classical music), Beethoven's ninth symphony (slow classical), rap (the Red Hot Chilli Peppers), Vivaldi (fast classical) and techno music.
Faster music and more complex rhythms speeded up breathing and circulation, with fast classical and techno having the greatest impact. Slower or more meditative music had the opposite effect with the raja music creating the largest fall in heart rate.
The authors conclude that certain types of music could be helpful in preventing heart disease.
Anyone for a statin, raja music and an exercise bike?
Dr Muiris Houston is pleased to hear from readers at mhouston@irish-times.ie but regrets he cannot answer individual queries.